Electric lamp base



Feb. 17, 1948. KE|FFER 2,436,259

ELECTRI C LAMP BASE Filed March 8, 1946 lnvewtor: Lawrence R. Idei++er3 b5 His A++W Patented Feb. '17, 1948 ELECTRIC LAMP BASE Lawrence R. Keiffer, Cleveland Heights, Ohio, assignor to General Electric Company, a cor poration of New York Application Marclr8, 1946, Serial No. 652,943g

9 Claims. ll

through the bottom of metal cups theedges of which are embedded into and fused to a relatively heavy, thick-walled neck at the vertex of the reflector section of the bulb. The neck has a fiat end wall and openings in registry with the cups and through which the support wires pass. Heretofore such lamps have been provided with screw type bases having a skirt which fits the outer surface of the neck and which has indented portions engaging indented portions in said neck surface to hold the base on the bulb. Such lamps are disclosed in U. S. Patent 2,262,629 issued November 11, 1941, and assigned to the assignee of this application.

Suchcommercial lamps and the sockets therefor require a space of at least six inches in depth for proper mounting. In many lighting installations it is inconvenient and many times impossible to provide a space of such depth for the lamps. This is particularly true in lighting installations comprising fluorescent lamps mounted close to the ceiling for providing general illumination and in which spot lights are desirable for providing a higher level of illumination on localized areas, such as display counters. Frequently, in such installations, the spotlight must be either recessed 3 into the ceiling or be allowed to extend below the fluorescent lamps.

The principal object of my invention is to provide a base for lamps of the above type which is shorter in length than the present bases. Another object of my invention is to provide a lamp of the above type which is shorter than the present lamps. Further objects and advantages of my invention will appear from the following detailed description of species thereof and from the appended claims.

In the drawing accompanying and forming part of this specification an embodiment of my invention is shown in which Fig. 1 is a perspective view of an electric lamp provided with my new base and as seen from above and Fig. 2 is an exploded view of the base showing in perspective its various parts and a fragmentary view of the lamp bulb; Fig. 3 is a top plan view of the neck portion of the bulb and the interior parts of the assembled base;

2 Fig. 4 is a side elevational view of the neck and the base with part of the base shell'cut away and Fig. 5 is a front elevational view of another species of base of my invention.

Referring to Figs, 1 to 4 of the drawing, the glass bulb of the lamp is shown at I and the base at 2. The base 2 comprises a cup-shaped metal cap 3 which engages the outer surface 4 0f the thick neck 5 of the glass bulb l and is firmly held thereon by at least two indented parts 6 which are 180 degrees apart and engage similarly spaced in dentations l in the outer surface 4 of the neck 5. A pair of contact prongs 8 extend outward through an opening 9 in the side of the cap and at right angles to the axis of the lamp for engagement with a suitable socket (not shown) which may be of conventional structure to accommodate the base prongs 8. Inasmuch as the prongs 8 and the socket are at the side of the base 2 rather than at its top and are transverse to the lamp axis rather than parallel thereto the mounting space for the lamp is considerably reduced. For example, a commercia. lamp having the designation Par-38 and provided with a screw type base extending along the lamp axis requires a mounting space of six inches in depth. The same lamp provided with my new base requires a mounting space of but four inches in depth.

Asshown in Figs. 2, 3 and 4 the base also comprises a thin, flat electrically insulating piece l0 which rests on the flat end wall H of the neck 5 and extends outward through the opening 9 to electrically insulate the prongs 8 from the cap 3. A spacer l2 of electrically insulating material, such as asbestos board, which has a pair of straight slots l3 for accommodating the prongs 8, rests on the insulating piece I0, holds the prongs 8 upright in spaced relation and extends through the opening 9 in the cap 3 to electrically insulate the prongs 8 from each other and from the cap 3. The spacer l2 and the piece l0 form an electric insulator which rests on the wall ll of neck 5 and insulates the prongs 8 from the cap 3. The prongs 8 have semi-circular depressions, or notches M which are engaged by transverse pro jections or ridges l5 (Figs. 2' and 4) at the bottom of the slots l3 in the spacer l2 to prevent movement of the prongs 8 along the slots I3 .when the prongs are inserted or removed from a socket. As best shown in Figs. 3 and 4, when the base is assembled on the'bulb, the straight back flat surface l6 and ll of the spacer l2 and the piece II], respectively, rest against the metal cups I8 which are embedded and fused into the neck 5 of the bulb I the rounded sides of these members 12 and 3 l engage the cylindrical inner surface of the cap 8 and the top of the spacer l2 engages the top of the cap 8. The spacer l2, the piece l8 and the prongs 8 are thus clamped to and firmly held in position on the'bulb 2 by the cap 8 to resist the forces tending to move the prongs 8 when the base 2 is moved into and out of engagement with a socket. The portions i8 of the prongs 8 adiacent their inner ends are curved to extend beyond the cups I8 (Figs. 3 and 4) and have ears. 28 which are pierced as shown at 2| to accommodate the external portions of the current leading-in wires 22 which are fused gas tight to and pass through the bottom of the cups l8 into the interior oi the bulb l. The cups i8 and the leadingin wires 22 constitute spaced electric terminals secured to the neck 8 and extending parallel to the axis of the reflector portion oi the bulb l. The wires 22 supp r the light emitting filament (not shown) in the bulb and maybe fastened, as by spot welding or soldering. to the ears 20 to electrically connect the prongs 8 with the filament. Since the prongs 8 are held stationary by the lamp members described above there is no physical force exerted on the connection between the prongs 8 and the wires 22 when the prongs 8 are moved into and out of a socket and the wires 22 thus may be fastened directly to the prongs 8 and the ears III omlttedii desired.

The base 2 maybe mounted on the lamp by placing the insulating piece II on the flat end surtace ll of the neck portion 8, the prongs 8 may then be placed on the insulating piece l8 with the wires 22 passing through the holes 2i in the cars 28. The spacer i2 is then placed over the prongs 8 and the wires 22 may then be welded to the upper surfaces of the ears 28. The cap 8 is then placed on the bulb I with the opening 8 in registry with portions of the prongs 8. the spacer l2 and the insulating piece l8 which protrude beyond the side surface 8 of the neck 8. The slightly iiared rim 28 of the cap 8 is then forced down over the slightly tapered outer surface 8 of the neck 8 to make a press flt therewith and until it enga es the shoulders 28 on the bulb l. The closed end of the cap 8 is spaced suiilciently from the cars 28 to avoid short-circuiting or the prongs 8 and engages the top of spacer l2 to clamp the latter to the neck 8. The cap 8 may then be indented as shown at 8 to engage the indentations I provided in the side surface lof the neck 8 to secure the assembled base 2 firmly tothe bulb I. The cap 8 has a pair of diametrically opposed longitudinally extending slits 28 which facilitate placing the cap on the neck 8.

As shown in Fig. 5, the thin insulating piece ill socket supported by the lamp. or the lamps may be supported by a socket engaging both the cap 8 and the prongs 8 or the prongs 8 alone.

may be omitted provided the bottom of the opening 28 in the cap 8 is spaced sufliciently from the prongs 8 to avoid short-circuits. In this embodiment the prongs 8 and the spacer l2 rest directly on the flat surface Ii of the glass neck 8 and the bottom edge of the opening 28 is spaced a greater distance from the prongs 8. While the bottom edge may be straight, I prefer to provide two semi-circular notches 21 opposite the prongs 8. I! the cap 8 should he accidentally displaced upward on the outer surface 8 of the bulb neck the prongs 8 would not be short-circuited by the cap 8 because the bottom edge of the opening 28 would engage the spacer l2 rather than the prongs 8 because of the provision o1 notches 21 in the said What I claim as new and desire to secure by Letters Patent of the United States is:

l. A projector lamp comprising a bulb having a light concentrating reflector portion with a short neck portion at the apex thereof and a base on said bulb neck comprising a comparatively shallow shell portion having contact prongs projecting therefrom transversely to the axis of said reflector portion to minimize the axial dimensions of said lamp.

2. A projector lamp comprising a bulb having a light concentrating reflector portion and a base attached to the apex of said bulb portion comprising a shallow cylindrical cap having contact prongs projecting therefrom transversely to the axis of said reflector portion to minimize the axial dimensions of said lamp.

3. In an electrical device comprising a bulb having a'relatively heavy glass neck with spaced electric terminals externally protruding therefrom, a base comprising a metal cap enclosing said terminals with its rim secured to and surrounding said neck, contact prongs electrically connected .to said terminals and projecting through an opening in the side of said cap for connecting said terminals to socket contacts for said device and an electrical insulator member having spaced slots accommodating and engag ing said prongs and being interposed between said cap and said prongs and clamped against said terminals and said neck by said cap to hold said prongs in fixed position on said device.

4. In an electrical device comprising a bulb having a relatively heavy glass neck with spaced electric terminals externally protruding there from, a base comprising a metal cap enclosing said terminals with its rim secured to and surrrounding-said neck, contact prongs electrically connected to said terminals and projecting; through an opening in the side of said cap ior connecting said terminals to socket contacts for said device and an electrical insulator member having spaced slots accommodating and engaging said prongs with projections in said slots engaging depressions in said prongs and being interposed between said cap and said prongs and clamped against said terminals and said neck by said cap to hold said prongs in fixed position on said device.

5. A short base for an electric device having externally protruding electric terminals on a glass neck portion. comprising a cup-shaped metal cap for engaging said neck portion and enclosing said terminals, contact prongs extending through an opening in the cylindrical side wall of said cap for connecting said terminals to socket contacts for said device and an insulator member having spaced slots accommodating said prongs and being interposed between said cap and said prongs and clamped against said terminals and said neck by said cap to hold said prongs in fixed position on the device.

6. A short base for an electric device having externally protruding electric terminals on a glass neck portion, comprising a cup-shaped metal cap for engaging said neck portion and enclosing said terminals, contact prongs extending through an opening in the cylindrical side wall of said cap for connecting said terminals to socket contacts for said device and an insulator member having spaced slots accommodating said prongs with projections in said slots engaging depressions in said prongs and being interposed between said cap and said prongs and clamped against said terminals and said neck by said cap to hold said prongs in fixed position on the device.

'7. In an electric lamp comprising a bulb having a light concentrating reflector portion and a relatively heavy glass neck in back oi the reflector portion with spaced electric terminals externally protruding therefrom parallel to the axis of the reflector portion, a base comprising a metal cap enclosing said terminals with its rim secured to and surrounding said neck, spaced electric contact prongs electrically connected to said terminals, and projecting transversely of the reflector axis through an opening in the side or said cap for connecting said terminals to socket contacts for said lamp and an electrical insulator member engaging said prongs and being clamped between said cap, said terminals and said neck to hold said prongs in ilxed position on said bulb.

8. In an electric lamp comprising a bulb having a light concentrating reflector portion and spaced electric terminals externally protruding from said portion and parallel to the axis thereof, a base 2 comprising a metal cap enclosing said terminals and attached to said Portion. spaced contact prongs electrically connected to said terminals and proiecting transversely of the reflector axis through an opening in the side of said cap for connecting said terminals to socket contacts for 30 228.95

said lamp and an electrical insulator member engaging said prongs and being clamped between said cap and said bulb to hold said prongs in fixed position on said bulb.

9. In an electric lamp comprising a bulb having a light concentrating reflector portion and spaced electric terminals externally protruding irom said portion and parallel to the axis thereof, a base comprising a hollow member enclosing said terminals and attached to said portion and spaced contact prongs electrically connected to said terminals and projecting from the side or the base transversely or the reflector axis for connecting said terminals to socket contacts for said lamp.

LAWRENCE R. KEIFF'ER.

summer-1s CITED The following references are of record in the tile of this patent:

UNITED STATES PATENTS Number Name Date 1,712,027 Cooke May 7, 1929 2,071,948 Peters Rb. 33, 1937 2,252,478 Wright Aug. 12, 1941 FOREIGN PATENTS Number Country Date Germany Sept. 11. 1009 

